The invention relates to apparatus for holding disk-shaped substrates in the vacuum chamber of a coating or etching apparatus, having a planar substrate bed with a preferably rectangular plan, especially for fastening to a rotating drum.
In practice it has proven to be problematical to arrange thin substrates of fragile material, such as wafers, on the substrate holder so that they will not slip off when the substrate holder is rotated to a vertical position. Also, it has proven to be difficult to assure sufficient cooling of the substrates when they are so thin that even very slight clamping forces result in a flexing of the substrate, so that the substrates no longer lie with their full surface against a water-cooled substrate bed.